Research on Fretting Wear of Grid and Cladding Tube Under Simulated Primary Circuit Environment of Pressurized Water Reactor

Abstract

Abstract With the deepening of the fretting wear process, the wear behavior and wear mechanism of the contact surface between the grid and the fuel rod cladding will gradually change, but there are relatively few research reports in this area at home and abroad. In this paper, the chemical environment of high temperature and high pressure water in the primary circuit of the PWR is simulated. In this environment, the friction pairs formed by the grid and the cladding tube are subjected to fretting wear tests of different durations (192h, 288h, 384h). The cladding samples is subjected to wear scar detection, and the wear topography data (including the wear volume and maximum wear depth) of the contact point between the cladding tube and the grid clamping system are obtained, and the wear coefficient is finally calculated using the ARCHARD equation. The results show that with the increase of the test time, the spring wear scar data (including the wear volume and the maximum wear depth) formed by the grid spring and the cladding tube tend to increase, the wear rate is basically stable at 0.8μm3*s−1, and the wear coefficient is basically stable at 0.4 × 10−17 Pa−1, there is no obvious change. For the dimple wear scar formed by the dimple of grid and the cladding tube, the wear scar data (including the wear volume, the maximum wear depth and the wear coefficient) are significantly greater than those obtained under the test conditions of 192h and 288h at 384h. However, the data obtained at192h is slightly larger than that at 288h, combining with the Archard equation, it can be seen that this may be caused by the decrease in the wear rate and wear coefficient in the middle of the fretting wear. The results of this paper show that with the deepening of the fretting wear process, the wear characteristics of the grid and cladding samples are constantly changing, it has a good reference significance for the existing fretting wear research between the grid and the cladding tube and the related nuclear fuel structure.